Could face-centered cubic titanium in cold-rolled commercially-pure titanium only be a Ti-hydride?

A face-centered cubic (FCC) phase in electro-polished specimens for transmission electron microscopy of commercially pure titanium has sometimes been reported. Here, a combination of atom-probe tomography, scanning transmission electron microscopy and low-loss electron energy loss spectroscopy is employed to study both the crystal structural and chemical composition of this FCC phase. Our results prove that the FCC phase is actually a TiHx (x >= 1) hydride, and not a new allotrope of Ti, in agreement with previous reports. The formation of the hydride is discussed. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.